Recently, the general trends in designing electronic devices are toward small size, light weightiness and easy portability. Moreover, with the increasing development of electronic industries, the internal circuitries of the electronic devices are gradually modularized. In other words, several electronic components are integrated into a single circuit module. For example, a power module is one of the widely-used circuit modules. The power module may be applied to an inverter, a converter, an electric vehicle (EV) or a hybrid electric vehicle (HEV). After the electronic components (e.g. capacitors, resistors, inductors, transformers, diodes and transistors) are integrated as a power module, the power module may be installed on a motherboard or a system circuit board.
Conventionally, the package structure for the power module is a housing package structure. That is, a direct bond copper (DBC) substrate that has good heat-dissipating efficacy and withstand higher voltage is used as a substrate. Moreover, several power semiconductor bare chips, passive components and pins are located at a first side of the DBC substrate. Through the pins, the package structure may be connected with an external device or an external component. The power semiconductor bare chips, the passive components and the pins are mounted on the DBC substrate through solder paste. Moreover, the power semiconductor bare chips may be connected with the external device or the external component through aluminum wires, gold wires, copper wires, ribbon bonds or copper clippers. Moreover, the first side of the DBC substrate is covered with a plastic housing. After plastic housing is fixed on the DBC substrate through adhesive or glue, silicone gel is injected into the space between the plastic housing and the DBC substrate in order to protect the power semiconductor bare chips and provide an insulating function. After the silicone gel is solidified, the plastic housing is covered by a top cover. Meanwhile, the procedure of fabricating the housing package structure is completed.
Although the DBC substrate may provide good heat-dissipating efficacy and withstand higher voltage, the conventional housing package structure still has some drawbacks. For example, in the conventional housing package structure, the power semiconductor bare chips, the passive components or other electronic components are only permitted to be mounted on a first side of the DBC substrate. In other words, these electronic components are only mounted on the DBC substrate in a 2D configuration. Moreover, since the electronic components are arranged on the same layer of the DBC substrate, the traces between the electronic components are still long. Under this circumstance, the line impedance is high, and a parasitic effect is easily generated. In other words, the electrical properties are possibly unsatisfied. Moreover, the power module with the conventional housing package structure is installed on a motherboard or a system circuit board by inserts or screws. In other words, the conventional housing package structure is not fixed on the motherboard or the system circuit board by a reflowing process. Consequently, the applications of the conventional housing package structure are restricted.
Therefore, there is a need of providing an improved package structure in order to eliminate the above drawbacks.